Low donor content solar cells utilising a fullerene acceptor are interesting as they have remarkably high open circuit voltages and reasonable efficiencies in spite the of the donor only being present in a few wt%. Various explanations of how they work have been put forward but in a recent paper COPE and colleagues have shown using molecular dynamics simulations that the donor materials are distributed in the films at a distance that can enable a percolation pathway for charges to be extracted in spite of their concentration being below the expected percolation limit.

Shanshan Zhang, a PhD student at COPE has been working with the group of Professor Dieter Neher (Potsdam University) on perovskite solar cells. A highlight of the work was a 1 cm2 inverted solar cell with a certified efficiency of 19.83%, which was published in Nature Energy.